Bobbed M931 almost done, Pics soon! A few questions please...

[wheelspinner]

As far as your question about the heater cord, I secured mine just inside the inside wheelwell on the frame rail by the tranny cooler. Just lift up the rubber and plug it in. Then the rubber keeps junk out of the plug when driving. Worked well for me.

 

[CBR Metalworks]

Hate to say it like this, I was going to stay out of this altogether (what has been said about the blocks being unsafe is true), but your suspension 'experts' are sound like a couple of idiots... Holes in the bottom of the frame will not weaken it (at least not enough to matter). Go look at how the front springs hangers are mounted, yup, holes on the bottom of the frame....

 

[joesco]

As a member, contributor and supporter of the SS Forum, since 2007, I find it a bit troubling that a Vendor on this forum, who hasn't even inspected my truck, call the suspension guys (with 50 years combined experience) who spent a considerable amount of time under my truck idiots. I would expect a Vendor member to provide "constructive" criticism, but I guess it all comes down to the character of the individual.

In an effort to keep this forum as a great resource to its members, I would like our moderators to delete this thread, if members use it to disparage instead of providing helpful comments and suggestions as others have. Thank you!

Hate to say it like this, I was going to stay out of this altogether (what has been said about the blocks being unsafe is true), but your suspension 'experts' are sound like a couple of idiots... Holes in the bottom of the frame will not weaken it (at least not enough to matter). Go look at how the front springs hangers are mounted, yup, holes on the bottom of the frame....

 

[CBR Metalworks]

OK, maybe they are not idiots, but any 'expert' should be able to come to the conclusion that if the military designed the front suspension with holes in the bottom of the frame, then holes in the bottom of the frame with identical style suspension (although from a trailer instead of a truck), that holes in the bottom of the frame should not weaken it.

What it sounds like to me is someone did not want to drill holes in the bottom of the frame (it is a tough task no doubt with a hand drill) and took the 'weld the hole' route. If those two small plug welds fail there is no way those two upper bolts will hold those spring hangers in place.

The hangers have nothing to do with 8" of lift blocks being unsafe, if this were an off road only truck it would not matter so much, but when the hangers or blocks fail going down the highway, you better hope nobody is behind you because it is going to be one heck of a show.

 

[CBR Metalworks]

This is me trying to be polite and help save the lives of passing motorists. If you run it as-is you might want to have the maximum limits non your liability insurance coverage.

 

[joesco]

I owe an apology to CBR and ALL others on this forum regarding the input on my M931 Bobbed job. I solved my fuel problem, (by installing 2 Baldwin filters and switching tanks) so I went down to top off the driver's side tank and get my inspection sticker.

After going to the four different shops, two that I knew very well, I sensed I was in deep dodo, no state inspection!!!!! So I headed back home and unfortunately or I should say fortunately, about a mile from my home, I got pulled over by a law enforcement officer. All I can say, I am eating so much crow right now, I am chocking to death!!!! Luckily I knew the officer and avoided a whole bunch of fines as long as I correct the suspension, BLOCKING AND SPRING HANGERS and keep the truck OFF THE ROAD until repaired. I will quote him, "Joe you hit one to many frost heaves in this truck today and you see your rear end in the side view mirrors and not on the truck!!!

So now I am on the hunt for a front 5 ton spring set. I am going to have this suspension "ripped" out and done right. So if I can ask, I would appreciate any details and pictures of your bobbed 5 ton as that will really help me out. Also, if anyone has a front 5 ton spring set for sale, please PM me. Thanks!!!

This is me trying to be polite and help save the lives of passing motorists. If you run it as-is you might want to have the maximum limits non your liability insurance coverage.

 

[CBR Metalworks]

This is how I have done them, 5-ton front springs, custom made u-bolts, and a spacer about 1.5" tall. Blocks are never an ideal solution for any suspension problem, but when kept below 3" they aren't too awful bad. On a heavy duty truck like these I personally would not want to use a block taller than 1.5"-2". Blocks contribute to axle wrap, so with the weight/torque these trucks put out coupled with 8" of lift block AND springs too light for the job (m105 springs) bad things can happen. 8" blocks would have very bad axle wrap even with the 5-ton springs.

Sometimes it takes a friend to talk you into something stupid, but there are also times friends talk you out of stupid things too!!

I am honestly surprised that the inspection stations failed it, I am GLAD there are some stations out there that actually still do a good job of looking at stuff like this! (assuming they all failed it because of the blocks).

 

[jesusgatos]

Happy to hear that you've got such a good attitude about all this, and that you're going to rework the rear suspension. We're all learning and sharing here, sometimes from each others' mistakes. Like this stupid mistake I made last weekend. But you'll find plenty of help here if you want it, and your truck will turn out better in the end. Cheers.

 

[joesco]

Thanks but it is also frustrating also. Over the last 7 years, this forum has been a life and time saver for me!!! Invaluable!

Happy to hear that you've got such a good attitude about all this, and that you're going to rework the rear suspension. We're all learning and sharing here, sometimes from each others' mistakes. Like this stupid mistake I made last weekend. But you'll find plenty of help here if you want it, and your truck will turn out better in the end. Cheers.

 

[aheilmann68]

I did not want to get involved with this thread earlier as enough people were reccommending that you had a sub par design. http://www.steelsoldiers.com/showthread.php?109192-M931-Bobber-Project-With-Air-Ride&highlight=
That is the first truck I did with air ride, just finished another and starting a third shortly. The suspension is a freight liner rear end remounted up to the frame. The panhard bar is the worst part due to real estate inside the frame (air line, abs controllers, frame stiffeners). This truck has 1, 500 miles on it already and is smooth and hauls. The bags are not in the optimal ride range but there are no adverse effects

 

[joesco]

Thanks for the detailed description and pics. Stupid question... Will I have to disconnect everything, including the drive shaft to install the new spring setup? Inspections were to fail for both the perches / hangers and blocks.

This is how I have done them, 5-ton front springs, custom made u-bolts, and a spacer about 1.5" tall. Blocks are never an ideal solution for any suspension problem, but when kept below 3" they aren't too awful bad. On a heavy duty truck like these I personally would not want to use a block taller than 1.5"-2". Blocks contribute to axle wrap, so with the weight/torque these trucks put out coupled with 8" of lift block AND springs too light for the job (m105 springs) bad things can happen. 8" blocks would have very bad axle wrap even with the 5-ton springs.

Sometimes it takes a friend to talk you into something stupid, but there are also times friends talk you out of stupid things too!!

I am honestly surprised that the inspection stations failed it, I am GLAD there are some stations out there that actually still do a good job of looking at stuff like this! (assuming they all failed it because of the blocks).

View attachment 481185View attachment 481186

 

[Recovry4x4]

Late to the game here. I'm glad that in the end, feelings were patched up and a new plan hatched. The geometry of the installed track bar along with the blocks would have made for some interesting conflict as they were certainly fighting each other. Statically they are a great idea by dynamically could have caused some issues. Thanks for sticking out the criticism. Many members point out the issues and often sound like alarmists but when it's all over they are just pointing out (sometimes abrasively) issues that cause concern.

 

[CBR Metalworks]

Thanks for the detailed description and pics. Stupid question... Will I have to disconnect everything, including the drive shaft to install the new spring setup? Inspections were to fail for both the perches / hangers and blocks.

Technically you may not have to disconnect everything, you will have to drill a total of 16 holes for the 5-ton springs, and you will need a 1-1.5" lift block, the original u-bolts will barely work with a 1" block, but probably better to replace them. Get ready to have some fun with a 1/2" drill, and hope you have some equipment to do the heavy lifting, or some strong friends, those springs are VERY heavy.

 

[tim410]

If you know anyone with access to a mag drill they will save you a ton of time and cursing. I drilled all 16 holes in about 45 mins with same drill bit. And that is measuring and marking holes and drilling in 45.

 

[aheilmann68]

Mag drill and annular cutters, it takes longer to measure out everything and mark it then to drill the holes.

 

[joesco]

State Inspection Failed, as expected, but two minor light issues.

I finally found A great truck shop in NH to inspect my truck and as expected, my suspension is not Road worthy, so I failed. I have an appointment on Monday with a local spring shop to deal with the suspension issues.

During his inspection, he also found two warning lights not operating, low air pressure and park brake. Bulbs are fine, along with the low warning buzzer, but there isn't any illumination. Went through TM 10 without success. Any suggestions?

Also my rear park breaks are out also. Napa for those bulbs? Part number? Thanks folks!

 

[Vintage iron]

Seems you have had nothing but bad luck with your truck. I hope you get your rear suspension worked out. You can get the numbers off your bulbs.

 

[MtnSnow]

Here you go for bulb numbers and cross reference for 6, 12 and 24 volt systems.

 

[porkysplace]

This is just a wild guess since you haven't post what kind of truck your working on , but if it is a 939 series 5 ton your going to need to download this for a wiring diagram to track down the light problems . M939_P2P.zip

 

[twinturb089]

Needs a failsafe module, very common when both lights dont work